1. Field of the Invention
The invention relates to a vitrified bonded grinding wheel that is formed so that superabrasives, such as cubic boron nitride (CBN) grains or diamond grains, are bonded with an amorphous glass binder.
2. Description of the Related Art
In a prior art, there is a vitrified bonded grinding wheel that is a grinding wheel using vitrified glass as a binder. The vitrified bonded grinding wheel is generally formed so that superabrasives are bonded with an amorphous glass binder in a state called bond bridge. Large open pores that are in fluid communication with outside air are formed between the adjacent bond bridges. Therefore, there is a problem in terms of abrasive grain holding strength, and abrasive grains early drop off, so the conventional vitrified bonded grinding wheel is unsuitable for heavy cutting, or the like. Then, for example, Japanese Patent Application Publication No. 2002-224963 (JP-A-2002-224963) describes a vitrified bonded grinding wheel that eliminates pores from an amorphous glass binder to improve superabrasive holding strength to have the vitrified bonded grinding wheel compatible with heavy cutting.
However, in the vitrified bonded grinding wheel described in JP-A-2002-224963, the amorphous glass binder has no pores, so there is a problem that dressing is difficult and dressing work is time-consuming.